High pressure Raman study of La${}_{1-x}$Ca${}_x$MnO${}_{3-\delta }$ manganites

Abstract

We report on a high-pressure Raman study on two members of the La${}_{1-x}$Ca${}_x$MnO${}_{3-\delta }$ manganite family ($x=0.20$, $\delta =0$ and $\delta =0.08$). The results obtained for the $\delta =0$ sample show a different behavior in the low and high pressure regimes ascribed to the onset of a new pressure-activated interaction previously invoked in other manganite compounds. The comparison of our results with literature data gives further support to the identification of the Jahn-Teller active stretching mode and shows that pressure-induced octahedral symmetrization is more effective in systems exhibiting a lower metallic character. On the contrary the new interaction sets in at pressure which decreases on increasing the metallic character of the system indicating a relevant role of the Mn-Mn hopping integral in its activation.

arXiv comment4 pages, 3 figure, submitted to Phys. Rev. B

References in corpus (8)

• Double Exchange Alone Does Not Explain the Resistivity of $L{a}_{1-x}S{r}_{x}Mn{O}_3$
• Pressure-tuning of the electron-phonon coupling: the insulator to metal transition in manganites
• Pressure effects on charge, spin, and metal-insulator transitions in narrow bandwidth manganite Pr${}_{1-x}$Ca${}_x$MnO${}_3$
• Effects of Pressure on Electron Transport and Local Structure of Manganites: Low to High Pressure Regime
• Correlations between pressure and bandwidth effects in metal-insulator transitions in manganites
• Transport and structural study of pressure-induced magnetic states in Nd0.55Sr0.45MnO3 and Nd0.5Sr0.5MnO3
• Pressure Induced Reentrant Electronic and Magnetic State in Pr0.7Ca0.3MnO3 Manganite
• High-Pressure Phase Diagram in the Manganites: a Two-site Model Study